bremner



Sept. 13, 1927.

F. D. H. BREMNER BLOW-OUT ARRANGEMENT FOR ELECTRIC SWITCHES Filed Aug.19, 1925 2 Sheets-Sheetl Jrrmysr Se t. 192

p 7 F. D. H.'BREMNER BLOW-OUT ARRANGEMENT FOR ELECTRIC SWI'ITCHES FiledAug. 19, 1925 Z'SheetSPSheetZ ATTORNEY Patented Sept. 13, 1927.

UNITED STATES PATENT OFFICE.

FRANCIS DONALD HOLDEN BREMNER, OF LONDON, ENGLAND, ASSIGNOR TO .THE ENG-LISH ELECTRIC COMPANY LIMITED, OF LONDON, ENGLAND, BRITISH COMPANY.

BLOVV-OUT ARRANGEMENT FOR ELECTRIC SWITCHES.

Application filed August 19, 1925, Serial No. 51,202, and in GreatBritain September 12, 1924.

There are many cases where an electric switch has to break a current ofconsiderable magnitude in a location where it is difiicult to providethe space necessary for drawing out and extinguishing the arc. Thesecond1- tions arise more particularly where a number of such switcheshave to be grouped together as, for example, in the case of multipleunit traction equipment using motor coaches where it is usual to mountthe switches controlling the motor circuits of each coach in the spacebeneath the floor of the coach. In this instance, the total availablespace is limited and in addition to that it is desirable or convenienceof actuation to group the switches as close together as possible.

The present invention deals with the difiiculty above indicated andconsists in pro viding that the principal part of the drawing out andextinguishing of the arc is performed by an auxiliary switch which canbe located at a reasonable distance away from the main circuit breakingdevice and is brought into circuit by the small are produced at thecontacts of the main circuit breaking device.

The invention will now be described by way of example with reference tothe ac companying diagrammatic drawings of which Figure 1 shows inelevation the contacts and are destroying arrangement of a main switchone side of the arc chute being removed and Figure 2 shows on the leftside a part sectional plan on the line II-II of Figure l and on theright side a part plan. Figure 3 shows in elevation portions of anauxiliary switch, including the contacts and the arc destroyingarrangement, one side of g the arc chute being removed, and Figure 4shows a section on the line IVIV of Figure 3. Figures 5 and 6 show viewssimilar to those shown in Figures 3 and 4 of a modified construction ofan auxiliary switch and Figure 6 is a section on the line VI-VI ofFigure 5. Figure 7 shows a diagram of connections for two mainswitchesand an auxiliary switch. The main switch (Figures 1 and .2) isarranged with are horns 1 and 2 in a chute 3 and provided with blow outcoil 1 and pole faces 5, but these members are of materially smallerdimensions than would be required if the whole extinction of the arewhich occurs upon opening contacts 6 and 7 were to be performed therein,since the energy to be dissipated within chute 3 each time the arc isbroken is a comparatively small part of thatpresent in the usualarrangement.

The main switch contacts 6 and 7 are shown in their closed positionsinto which they have been moved from the open position due to theenergizing of coil 27 of solenoid 31 which consequently lifts itsarmature 32 and communicates this motion to the moving contact 6 by wayof connecting rod 47 and member 16 which is pivotally connected at 28 toa fixed conducting member 34. As soon as the coil 27 is'de-energized thearmature 32 will fall (assisted by a biasing force such as a spring ifrequired) and will cause the moving contact 6 to move to the left.Current enters the main switch at terminal 35 and passes through thewinding of the blow-out coil 4 to the conducting member 34 to which thehorn 1 is conductively fixed. The current thenpasses to the moving andfixed switch contacts 6 and 7 and to the fixed conducting member 29, towhich the horn 2 is conductively fixed, and out at the terminal 30.

To establish connection with the auxiliary switch additional horns orelectrodes 8 and will be quite independent of the main. circuit,

except when an arc exists, but where a single electrode is used one ofthe horns 1 and 2 of the main switch will be permanently connected witha contact of the auxiliary switch.

Electrodes 8 and 9 are preferably arranged with a barrier 10 ofinsulating material, for instance soapstone, placed between them, andprojecting as at 11 from their inner ends, so as to draw out the arc ofthe main switch between them. Electrode 8 is elec trically connectedthrough the cable 20 with one contact of the auxiliary switch, andelectrode 9 is electrically connected through cable 36 with theothercontact of the auxiliary switch, and the contacts 12 and 13 of theauxiliary switch Figures 3 and 4 are normally closed, so that theestablishment of the circuit through them by the arc is accompanied bythe extinction of that por ,tion of the are which is bridged by thecircuit including the contacts of the auxiliary switch.

The auxiliary switch shown in Figures 3 and 4 is so arranged that assoon as current passes through it the contacts 12 and 13 are separated,thus producing an are which strikes onto horns 14 and 15, and travelsoutwards on them until it is extinguished, this action being assisted bya powerful magnetic blow-out. extinction of the are at the auxiliaryswitch is accompanied by the extinction of the partial are or arcs atthe main switch.

The cables and 36 in Figure 1 are connected respectively to the terminallugs 37and 38 in Figure 3 so that current passes from the additionalelectrode 8 in Figure 1 through the coil 17 of the blow-out device inFigure 3 to lever 24, moving and fixed contacts 12 and 13, terminal 38and back by way or cable 36- to the additional electrode 9 in Figure 1.The arcing horn 14 is conductively connected through the member 33 tothe inner end of the coil 17 and the other horn 15 is conductivelyconnected to the fixed contact 13 and the terminal lug 38. In Figures 3and 4 the current passing through the blow-out coil 17 is utilized notonly to energize the core 18 and cheeks 19 of the blow-out magnet forthe are between contacts 12 and 13 but. also for attracting an armatureto operate the switch. This operation is carried out by providing on theiron circuit of the blow-out magnet aprojection or preferably a pair ofprojections 21 through whichpasses a small leakage field in which islocated an armature 22, coupled by nonmagnetic spindle 23 to lever 24,on which is mounted moving contact 12 of the auxiliary switch. Armature22 will usually be kept of small dimensions so as to restrict theleakage field. In order to assist in producing the rapid and cer tainopening of the auxiliary switch the connection between contact 12 andarmature 22 may include a pin and slot connection or equivalent freemotion device. For instance spindle '23 may be formed with slot throughwhich passes lever 24 which is pivoted at 26, so that armature 22 movesan appreciable distance before giving movement to lever 24, and thearmature has attained considerable velocity and reached a strong part ofthe attracting field before spindle 23 contacts with lever 24 and startsrotating it aboutpoint 26 to open contacts 12 and 13.

The auxiliary switch shown in Figures 5 and 6 difiers from that shown inFigures 3 and 4 in being provided with a blow-out coil which isenergized from a source distinct from the current which has to be- It isobvious that the interrupted. This coil is denoted by the numeral 39 andits terminals 40 and 41 are connected to some suitable source ofcurrent. The current to be interrupted passes from the cable 20(Figure 1) to the terminal 42, through the coil 43 of a solenoid devicefor operating the moving contact 12, to the lever 24 connected to thatcontact and thence to the fixed contact 13 and to terminal 44 which isconnected to the cable 36 in Figure 1. The energization of the coil 43causes the armature 45 of the solenoid device to rise together with thestud 46 to which it is connected. This stud then hits the lever 24 whichrises and takes with it the contact 12 and so opens the contacts 12 and13' of this auxiliary switch. The arcing horn 14 is conductivelyconnected to the contact 12 by way of the lever 24 and the horn 15 isconductively connected to the fixed contact 12. The magnetic cheeks 19are associated with theblow-out coil in the usual manner.

It will be seen that in many cases where a number of main switches aregrouped together, but not intended to be opened simultaneously, a singleauxiliary switch can be used in conjunction with them, the additionalelectrodes being connected in parallel. Fig. 3 shows two main switches'47 and 48 (which may be similar to Figure 1) each of which has itsadditional elec trode 8 connected through blow-out and operating coil 17of an auxiliary switch (which may be similar to Figure 3) to its movingcontact 12' whilst electrodes 9 are connected to stationary contact 13.

The invention is not limited to the precise arrangements shown in thedrawings which are susceptible to many modifications. Obviously. where asingle auxiliary switch serves a large number of main switches which arebeing continually brought into action for opening the circuit, it may beadvantageous to have the auxiliary blow out continuously energized asfor example in Figure 5. In this case, some independent means of openingthe auxiliary switch must be provided, such, for instance as a separateseries electrode-magnetic device (as for example in Figure 5) or adevice utilizing the electrodynamic action of the field produced by theblow out coil upon a conductor carrying the current which flows to theauxiliary switch.

lVhat I claim as my invention and desire to secure by Letters Patentis 1. A blow out device comprising a main circuit breaking device, anauxiliary switch 7 separate from the said main circuit breaking device,conducting. means tor carrying arc current between the main circuitbreaking device and the auxiliary switch, said means being adapted to bebrought into circuit by an are at the main circuitbreaking device whichis initiated by the normal functioning of said device when commencing toopen the circuit, and means associated with the auxiliary switch "forstopping the flow of are cur rent therethrough.

2. A blow out device comprising a main circuit breaking device, anauxiliary switch, means for blowing out an are at said auxiliary switchand means for connecting said auxilia 5* switch in series with the maincircut breakng device by way of an are at the main circuit device whichis initiated by the normal functioning of said device in com mencing'toopen the circuit.

A blow out device comprising a main circuit breaking device adapted toproduce an are when commencing to break the circuit, means for breakingan are at said circuit breaking device, an auxiliary switch, means forblowing out an are at said auxiliary switch, means for connecting saidauxiliary switch in circuit with the main circuit breaking device by wayoi the said are breaking means so as to bridge the break produced in thearc. thereby.

l. A blow out device comprising a main circuit breaking device adaptedto produce an are when commencing to break the cir cuit, an electrodelying in the path oi the are produced at said circuit breaking device,an auxiliary switch, means for blowing out an are at said auxiliaryswitch and means for connecting said auxiliary switch in circuit withsaid main circuit breaking device by way of said electrode.

A blow out device comprising a main circuit breaking device, arcinghorns on the main circuit breaking device between which an arc isestablished by the normal functioning of said device when commencing tobreak the circuit, two electrodes arranged between the arcing horns, aninsulating barrier placed between the electrodes and projecting beyondtheirinner ends, an auxiliary switch, means for conveying arc currentbetween the said electrodes and the auxiliary switch, and meansassociated with the auxiliary switch for stopping the flow of arccurrent therethrough.

(3. A blow out device comprising a main circuit breaking device adaptedto establish an are when commencing to break the circuit, an auxiliaryswitch separate from the main circuit breaking device, means forconducting arc current between the main circuit breaking device and theauxiliary switch, and combined means for opening the contacts andblowing out the arc of the auxiliary switch upon the flow of arc currenttherethrough.

7. A blow out device comprising a main circuit breaking device adaptedto establish an are when commencing to break the circuit, an auxiliaryswitch, means for conveying are current between the main circuitbreaking device and the auxiliary switch, a blow out magnet on theauxiliary switch, an armature adapted to be influenced by the blow outmagnet and opening means acting on a contact of the auxiliary switch andactuated by the said armature.

8. A'lilow out device comprising. a plurality of main circuit breakingdevices, each one of which is adapted to establish an are whencommencing to open its circuit, a single nxiliary switch, means forconducting arc current between each main circuit breaking device and theauxiliary switch, and means associated with the auxiliary switch forstopping the flow of arccurrent therethrough.

9. A blow out device comprising a main circuit breaking device adaptedto establish an are when commencing to open the cir- 'cuit, an auxiliaryswitch, means for conduct ing arc current between the main circuitbreaking device and the auxiliary switch, means including a coilinfluenced by arc current for opening the auxiliary switch and a blowout coil on the auxiliary switch, which coil is energized by currentfrom a separate source of supply.

In testimony whereof I afiix my signature.

F. D. H. BREMNER.

